The manufacture of semiconductors involves the patterning of semiconductor, dielectric and metallic films. This is accomplished by transferring a patterned photoresist or other masking layer to the desired film layer. This pattern transfer is typically accomplished using a plasma etch process.
Others have patterned layers of TiW less than two thousand angstroms in thickness. Most semiconductor processing does not use TiW layers greater than two thousand angstroms. The operation of certain electronic devices requires high currents. One example of such an electronic device is an MRAM or magnetoresistive memory. Because the currents are high, a suitable metal must be used that is resistant to electromigration problems. One such material is TiW. The thickness of TiW required to resist electromigration for MRAM devices is greater than two thousand angstroms. Current TiW etch processes have not demonstrated any plasma etch process with uniformity and selectivity suitable for use in production of very large scale integrated circuits with 0.5 micron design rules and with bit densities as high as one megabit per chip.
Therefore, there is a need to have a novel way of creating TiW structures two thousand angstroms thick and greater.
There is also a need for a novel method that provides uniformity and selectivity suitable for use in production of very large-scale integrated circuits with 0.5 micron design rules and with bit densities as high as one megabit per chip.